<template>
  <div class="home">
    <div class="home page-container">
      <!-- 导航栏 -->
      <div class="nav-bar">
        <div class="logo"></div>
        <van-button
          class="search-btn"
          round
          type="info"
          size="small"
          icon="search"
          @click="$router.push('/search')"
        >搜索</van-button>
      </div>
      <!-- /导航栏 -->

      <!-- 频道列表 -->
      <van-tabs
        ref="tabs"
        v-if="channels.length"
        class="fixed-tabs"
        v-model="active"
        swipeable
      >
        <van-tab
          :title="channel.name"
          v-for="channel in channels"
          :key="channel.id"
        >
          <!-- 文章列表 -->
          <Articlelist :channel="channel"></Articlelist>
          <!-- /文章列表 -->
        </van-tab>
        <!-- 它默认会把你写的其它内容渲染到内容的底部 -->
        <div
          slot="nav-right"
          class="van-tab"
          style="flex: 0 0 8%"
        ></div>
        <van-icon
          slot="nav-right"
          class="wap-nav"
          name="wap-nav"
          @click="isChannelEditShow = true"
        />
      </van-tabs>
      <!-- /频道列表 -->

      <!--频道编辑弹窗 -->
      <van-popup
        v-model="isChannelEditShow"
        position="bottom"
        :style="{ height: '100%' }"
        round
        :overlay="false"
        class="channel-edit-popup"
      >
        <van-nav-bar title="编辑频道">
          <van-icon
            name="cross"
            slot="left"
            size="20"
            @click="isChannelEditShow = false"
          />
        </van-nav-bar>
        <!-- $event表示事件参数 -->
        <Pindao
          :user-channels="channels"
          :active="active"
          @close="isChannelEditShow = false"
          @updateActive="active = $event"
        ></Pindao>
      </van-popup>
      <!-- /频道编辑弹窗 -->
    </div>
  </div>
</template>
<script>
import { getUserChannels } from '@/api/user'
import Pindao from './Pindao'
import Articlelist from './Articlelist'
import { getItem } from '@/utils/storage'
export default {
  name: 'HomePage',
  components: {
    Pindao,
    Articlelist
  },
  props: {},
  data() {
    return {
      active: 0, // 控制激活的标签页
      isChannelEditShow: false, // 弹窗的显示状态
      channels: []
    }
  },
  computed: {
  },
  watch: {
    // 当切换用户、用户退出、用户登录的时候更新频道列表
    user() {
      // 清空频道列表
      this.channels = []
      // 初始化激活标签
      this.active = 0
      // 等待视图更新 -> 重新加载频道列表
      // 注意：文章列表组件必须关闭滚动检查手动 onLoad，否则更新频道列表无法触发自动加载文章列表数据
      // this.$nextTick(() => this.loadUserChannels())
    }
  },
  activated() {
    // 如果没有频道数据，则请求加载
    if (!this.channels.length) {
      this.loadUserChannels()
    }
  },
  created() {
    this.loadUserChannels()
  },
  methods: {
    async loadUserChannels() {
      let channels = []
      if (this.user) {
        // 已登录，请求获取用户频道列表
        const { data } = await getUserChannels()
        channels = data.data.channels
      } else {
        // 未登录
        const localChannels = getItem('user-channels')
        if (localChannels) {
          // 使用本地存储的频道列表
          channels = localChannels
        } else {
          // 没有就使用默认推荐的频道列表
          const { data } = await getUserChannels()
          channels = data.data.channels
        }
      }
      this.channels = channels
    }
  }
}
</script>
<style lang="less" scoped>
.home {
  .nav-bar {
    position: fixed;
    top: 0;
    left: 0;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 15px;
    width: 100%;
    height: 46px;
    background-color: #3196fa;
    z-index: 1;
    .logo {
      background: url("./logo.png") no-repeat;
      background-size: cover;
      width: 100px;
      height: 30px;
    }
    .search-btn {
      background-color: #5babfb;
      width: 50%;
    }
  }
  .wap-nav {
    position: fixed;
    right: 0;
    background-color: #fff;
    opacity: 0.8;
    font-size: 26px;
    line-height: 43px;
  }
  /deep/ .van-tabs {
    .van-tab {
      border-right: 1px solid #edeff3;
      border-bottom: 1px solid #edeff3;
    }
    .van-tabs__line {
      width: 15px !important;
      background-color: #3296fa;
      bottom: 20px;
    }
  }
  .channel-edit-popup {
    border-radius: 10px 10px 0 0;
  }
}
</style>